Rescuers search for survivors in the debris after an earthquake hit Ludian county in Zhaotong, Yunnan province. Photo: AFP

Some 7,000 rescuers dug through shattered homes on Monday looking for survivors of a strong earthquake in Yunnan province that killed at least 398 people and injured almost 1,900.

About 12,000 mostly brick homes collapsed when the magnitude-6.1 quake struck on Sunday afternoon in the impoverished Ludian county, about 370km northeast of Yunnan’s capital, Kunming, Xinhua reported.

The streets of Ludian county seat of Zhaotong were like a “battlefield after a bombardment,” resident Ma Liya told Xinhua. She added that her neighbour’s house, a new two-storey building, had toppled, and said the quake was far worse than one that struck the area in 2012 and killed 81 people.

“I have never felt such strong tremors before. All I can see are ruins,” Ma said. “The aftermath is much, much worse than what happened after the quake two years ago.”

The magnitude-6.1 quake struck at 4.30pm on Sunday at a depth of 10km according to the US Geological Survey. Its epicentre was in Ludian county township of Longtoushan, where news website yunnan.cn reported 42,000 homes destroyed or damaged.

The China Earthquake Networks Centre put the magnitude at 6.5.

Rain and thunderstorms were forecast for the area in the coming hours, complicating efforts to bring tents, water, food and other relief supplies to survivors. Roads had caved in, and rescuers were forced to travel on foot.

The Yunnan Civil Affairs Bureau said on its website that 398 people were killed and 1,801 injured. Another 29,400 people were evacuated, CCTV said. The death toll is expected to rise after rescuers reach remote communities to assess casualties.

Many of the homes that collapsed in Ludian, which has a population of about 429,000, were old and made of brick, Xinhua said, adding that electricity and telecommunications were cut off in the county.

CCTV said it was the strongest quake to hit Yunnan in 14 years. It said a further 49 were killed and 102 injured in nearby Qiaojia county, while four died and dozens more were injured in Huize county.

Disaster struck at 4.30pm with strong tremors felt in several cities in Yunnan, including Qujing and Kunming, and further afield in Chongqing, Leshan and Chengdu in Sichuan province, and Xian in Shaanxi.

Longtoushan and nearby townships are about 50km away from downtown Zhaotong city, which is densely populated. Ludian's seven townships have a population of nearly 430,000.

The quake toppled and cracked many buildings, particularly old ones and residential homes, Xinhua reported.

A Ludian resident told Xinhua: "I felt a strong jolt in my fifth-floor home and some small objects fell off the shelves."

Another resident was driving his car when the earthquake struck and said it felt like he was "sailing a boat".

Almost all houses in a village in Zhichang township, Huize county, collapsed, leaving 11 people injured, the news website people.com.cn reported.

Internet users posted photos showing cracked walls, ruined buildings and people searching among the debris. Local people expressed anger online, blaming authorities for using hollow bricks in poor-quality buildings.

One resident told the South China Morning Post such buildings were common in rural areas of Zhaotong city because they were cheap to build. "They are the most dangerous buildings to be in during an earthquake."

More than 2,500 soldiers were rushing to the quake-hit areas. The civil affairs authorities are sending 2,000 tents, 3,000 folding beds, 3,000 quilts and 3,000 coats to the quake region.

The Red Cross Society of China allocated quilts, jackets and tents for those made homeless by the quake, while Red Cross branches in Hong Kong, Macau and neighbouring Sichuan province also sent relief supplies.

UN Secretary-General Ban Ki-moon on Sunday said that he was "saddened by the loss of life, and the damage to homes and infrastructure".

The secretary-general "offers his condolences to the Chinese government and the families of those killed, and his deepest sympathies to those who were injured or otherwise affected in this disaster," said a statement issued by Ban's spokesman.

"The United Nations stands ready to lend its assistance to efforts to respond to humanitarian needs created by the disaster and to mobilize any international support needed," the statement said.

In 1970, a magnitude-7.7 earthquake in Yunnan killed at least 15,000, and a 7.1 quake killed more than 1,400 in 1974.